THE  EFFECT  OF  OXYGEN  AND  CARBON  DIOXIDE  ON 
THE  CARBONIZATION  OF  COAL 

BY 

FLOYD  BEATTY  HOBART 
B.  S.  University  of  Illinois,  1920 


THESIS 

Submitted  in  Partial  Fulfillment  of  the  Requirements  for  the 

Degree  of 

MASTER  OF  SCIENCE 

IN  CHEMISTRY 
IN 

THE  GRADUATE  SCHOOL 
, OF  THE 

UNIVERSITY  OF  ILLINOIS 


1921 


V2>2.\ 

UNIVERSITY  OF  ILLINOIS 


THE  GRADUATE  SCHOOL 


July. 29, 1 92L 


I HEREBY  RECOMMEND  THAT  THE  THESIS  PREPARED  UNDER  MY 

SUPERVISION  BY Floyd.  Bea_tty  Hobart..  __ 

ENTITLED The  Effect  of  Oxygen  and  Carbon  Dioxide  on 

the  Carbonization  of  Coal . 


BE  ACCEPTED  AS  FULFILLING  THIS  PART  OF  THE  REQUIREMENTS  FOR 


Recommendation  concurred  in* 


Committee 

on 

Final  Examination* 


^Required  for  doctor’s  degree  but  not  for  master’s 


Digitized  by  the  Internet  Archive 
in  2015 


https://archive.org/details/effectofoxygencaOOhoba 


This  investiation  v/as  undertaken  at  the 
suggestion  of  Dr.  T.  E.  Layng.  He  has  given 
valuable  advice,  help  and  instruction  on  all 
occasions  during  the  investigation  and  I am 
deeply  indebted  to  him,  not  only  for  his  as- 
sistance in  this  particular  problem,  but  also, 
for  the  deeper  appreciation  of  research  that 
he  has  inspired,  and  I wish  to  sincerely 
thank  him. 

I wish,  also,  to  thank  Prof.  3. Vi".  Parr 
for  the  interest  he  has  shown  towards  this 
investigation. 


Table  of  Contents 


pages 

I.  Introduction. 

1.  nature  of  the  Problem  1 

2.  Historical 1 

3.  Outline  of  the  Present  Investigation....  8 

II.  Experimental. 

1.  Apparatus 9 

2.  Temperature  Control  and  lie  a sure  me  nt 12 

3.  Operation  of  Apparatus 13 

4.  Determination  of  Products  and  Analysis..  14 

5.  Types  of  Coal  Used 15 

III.  Results. 

1.  The  Effect  of  Carbon  Dioxide... 16 

2.  The  Effect  of  Oxygen 18 

IV.  Discussion  and  Conclusions 32 

V.  Summary 36 

VI.  Bibliography 37 


' 


1. 

THE  EFFECT  CF  OXYGEN  AND  CARBON  LIOXILE 
ON  THE  CARBONIZATION  OF  COAL. 

I.  Introduction. 

1.  Nature  of  the  Problem: 

This  problem  is  one  of  a series  of  closely  related  problems 
which  are  being  studied  in  this  laboratory,  with  a purpose  of 
learning  mor6  about  the  carbonization  of  coal.  Luring  previous 
work  it  was  observed  that  the  gases,  obtained  from  the  carboniza- 
tion of  non-coking  and  poorly  coking  coals,  held  large  percentages 
of  carbon  dioxide.  It  was  thought  at  the  time  that  this  carbon 
dioxide  was  responsible,  in  part  at  least,  for  the  non-coking  of 
these  coals.  Accordingly  this  problem  was  undertaken  as  a means 
of  learning  whether  or  not  carbon  dioxide  is  responsible  for  the 
non-coking  of  certain  coals.  After  some  investigation  it  was 
learned  that  it  would  be  advantageous  to  study  along  with  the  ef- 
fect of  carbon  dioxide,  the  effect  of  oxygen;  as  it  appeared  that 
the  carbon  dioxide,  formed  during  carbonization,  was  a result  of 
oxygen  present  in  the  coal. 

2.  Historical: 

There  is  nothing  in  the  literature  concerning  the  effect  of 

carbon  dioxide  on  the  coking  constituents  of  coal.  Anderson  and 

1 

Roberts,  during  tests  on  a large  number  of  coals  to  determine  the 
cause  of  coking  in  some  of  them  and  not  in  others,  "heated  these 
coals  (from  the  Clyde  Basin)  to  a temperature  of  500°  C.  for  three 
hours  in  an  atmosphere  of  dry  carbon  dioxide,  instead  of  gaining 


' 


2. 

in  weight  as  they  did  when  heated  in  air  to  between  100“’  and  150'  C., 
they  lost  in  weight.  The  non-coking  coals  lost  the  most  and  the 
coking  coals  the  least,  that  is  to  say,  the  humus  bodies  were  even 
at  this  temperature  beginning  to  decompose.  The  same  experiment 
showed  that  after  this  treatment  the  percentage  of  coke  was  in- 
creased (probably  fixed  carbon  is  meant,  as  only  three  of  the  coals 
coked),  and  that  in  the  feebly-coking  coals  the  power  of  coking 
was  entirely  destroyed,  but  only  impaired  in  the  true  coking  coals! 
The  authors  conclude,  nthat  in  all  the  coals  resinoid  bodies  ex- 
ist, which  can  be  saponified  by  caustic  potash,  and  which  alone 
are  accountable  for  the  coking  of  semi-coking  coals.  In  addition 
to  these,  in  the  true  coking  coals  there  is  a constituent  not  so 
easily,  if  at  all,  acted  on  by  alkalies,  oxidisable  in  air,  but 
not  volatile  at  300°  C."  They  find  also  "that  the  true  coking 
coals  melt  in  an  atmosphere  of  carbon  dioxide  at  317  C.",  and  this 
they  take  to  be  the  melting  point  of  the  constituent  referred  to. 

It  is  evident  that  Anderson  and  Roberts  saw  nothing  in  the 
behavior  of  coals,  when  in  an  atmosphere  of  carbon  dioxide,  to 
cause  them  to  believe  that  carbon  dioxide  had  a deleterious  effect 

upon  their  coking  constituents. 

2 

According  to  Anderson,  the  first  one  to  investigate  the  ef- 
fect of  heating  coal  in  air,  or  in  oxygen,  was  Prof.  Richter,  who, 
in  1870,  found  that  coal  heated  in  air  absorbed  oxygen,  and  that 
on  further  heating  the  percentage  of  fixed  residue  was  increased 
extraordinarily.  He  also  knew  that  some  of  the  ?as  coals  resisted 
the  absorption  of  oxygen  for  some  tine.  Anderson  investigated 
the  effect  of  oxygen  on  Scotch  coals  with  the  idea  of  determining 
the  nature  of  the  coking  constituent.  He  proved  the  validity  of 


« 


, ’ 


3. 

Richter's  work,  and  that  the  effect  of  oxygen  was  a destruction 
of  the  coking  properties,  especially  in  the  weakly-coking  coals. 

fhe  effect  of  oxygen,  that  is  in  the  original  combination  of 
the  coal  and  that  which  has  been  absorbed  by  weathering,  has  pro- 
bably been  noted  by  every  authority  who  has  studied  the  carboniza- 
tion of  coal  since  Richter's  publication  of  1870,  and  was  no  doubt 
noted  by  some  even  before  this  time.  The  earlier  investigation 
along  this  line  was  undertaken  with  the  idea  of  learning  more  a- 
bout  spontaneous  combustion  and  v/eathering,  and  their  causes.  On- 
ly recently  has  the  study  been  carried  on  to  a great  extent  with 

the  effect  on  coking  as  the  important  object. 

3 

White  claims,  that  the  coking  qualities  of  coal  depend  upon 
the  presence  of  certain  gelatinous  algae,  that  those  coals  which 
contain  the  greatest  quantity  of  micro-algae  shov;  hydrogen  and 
oxygen  in  almost  the  same  proportion  as  exists  in  bitumen,  that 
is,  they  have  the  highest  hydrogen  and  lowest  oxygen  content.  He 
therefore  concludes  that  coals  high  in  volatile  matter  and  whose 
analysis  show  sufficiently  high  bituminization  will  coke  by  the 
ordinary,  or  bee-hive  process,  and  that  the  degree  of  bituminiza- 
tion in  these  coals  is  indicated  by  the  relative  excess  of  hydro- 
gen as  compared  with  the  diminished  oxygen  in  dry  coal,  expressed 
by  the  ratio  of  hydrogen  over  oxygen(E:0). 

White  examined  and  compared  the  results  from  a large  number 
of  American  coals,  and  an  examination  of  his  results  shows  that  be- 
low the  highest  of  the  semi-bituminous  coals,  which  are  approaching 
the  anthracite  stage,  those  coals  with  a H:Q  ratio,  or  percentage, 
of  59  or  more,  but  with  one  or  two  exceptions,  make  coke  by  the 
ordinary  commercial  process.  Nearly  all  of  those  below  59  and  a- 


* • • Um  I 


4 


bove  55,  so  far  as  tested,  make  a coke,  and  among  those  with  a ra- 
tio of  between  55  and  50  a large  percentage  make  coke.  A few  of 
the  coals,  tested,  with  a slightly  lower,  ratio  also  make  coke, 
but  those  cokes  made  from  coals  with  a H:0  ratio  of  less  than  55 
are  usually  very  poor  and  apt  to  be  dark  and  brittle.  The  best 
cokes  are  made  from  coals  in  which  the  H:0  ratios  are  60  or  more. 
Other  factors  need  to  be  considered,  the  most  important  being  the 
fixed  carbon  content.  White’s  results  point  to  the  fact  that 
coals  of  less  than  79  per  cent,  fixed  carbon,  on  the  pure  coal  ba- 
sis, will  give  a true  index  of  their  coking  qualities  on  applica- 
tion of  the  H:0  ratio. 

In  coals  of  greater  than  79  per  cent,  fixed  carbon  it  is  gen- 
erally possible  to  produce  a coke  if  the  qunatity  of  carbon  in 
the  volatile  matter  is  relatively  large.  Also,  most  coals  in 
which  the  H:0  ratio  is  high,  but  which  refuse  to  coke,  are  distin- 
guishable by  their  clearly  defined  calorific  deficiency  with  re- 
ference to  the  carbon  : oxygen  f ash  ratio.  White  further  states 
that,  "the  changes  of  coal  on  exposure  or  weathering  are  indicated 
in  the  analysis  by  reduced  H:0  ratios;  by  reduced  available  hydro- 
gen; and  in  many  cases  by  reduced  volatile  carbon  ratios.  Weath- 
ering can  in  most  cases  be  detected  by  the  change  in  the  oxygen- 
hydrogen  relations  and  by  the  marked  calorific  deficiencies.” 
Considerable  data  relating  to  the  absorption  of  oxygen  by 

zi 

coal  is  available.  Anderson;  in  1898  found  that  at  temperatures 
below  160°  C.  atmospheric  oxidation  of  Scottish  coals  progressed 
rapidly  during  the  first  12  to  24  hours,  but  afterwards  fell  off 
considerably.  Nevertheless  the  coal  increased  slowly  in  weight 
for  a long  time,  the  period  varying  for  different  coals. 


. ... 

' 

v 


5 


Bone  mentions  that,  "the  Doncaster  workers  had  been  puzzled 
to  find  that  'in  the  oxidation  of  coal  at  low  temperatures  oxygen 
disappears  but  scarcely  any  carbon  dioxide  is  formed1 , but  this 
fact  was  surely  well  known  before  to  chemists  (S.W.Parr  in  parti- 
cular), and  need  cause  no  surprise  to  any  one  familiar  with  the 

phenomena  of  surface  combustion  generally." 

G 

Bone  has  experimented  on  the  absorption  of  oxygen  at  temper- 
atures between  45  and  120*  0.  on  a Durham  coking  coal  and  a Barns- 
ley hard  steam  coal.  He  found  that  at  temperatures  below  80  Q G. 
the  absorption  was  in  each  case  rather  slow,  even  under  increased 
pressure.  In  the  nieghborhood  of  80^  G.  the  reaction  became  de- 
cidedly quicker  and  at  above  100°  C.  it  was  marked  by  a regular 
and  simultaneous  production  of  the  two  oxides  of  carbon,  and  steam, 
these  evidently  resulting  from  the  decomposition  of  some  unstable 
body,  or  bodies,  primarily  formed  by  the  absorption  of  the  oxygen. 
These  tests  were  made  by  circulating  dry  oxygen  continuously  over 
the  previously  dried  coal.  Bon6  gives  quantitative  results  of 
the  tests  made  on  both  coals  at  107  to  109°  C.  which  are,  in  part, 
as  follows; 


Durham  Coking  Coal. 


Temperature 

100' 

200  * 

300  6 

400  * 

500 

0P  absorbed 

34.40 

57.90 

84.00 

9 7.40 

110.00 

COp  evolved 

4.27 

6.94 

9.30 

11.32 

GO  evolved 

1.92 

2.78 

3.63 

4.27 

. 


• 

♦ 

6. 


Barnsley  Hard  Stean:  Coal. 


Temperature 

100" 

200  ' 

300  * 

400° 

o 

500 

Op  absorbed 

57.50 

81.20 

96.00 

108.30  110.10 

COg  evolved 

7.60 

12.00 

14.40 

15.90 

CO  evolved 

5.90 

5.30 

5.76 

5.76 

Note.  The  volumes  of  gas 

are  in  c.c. 

per  gram 

of  coal. 

Bone  says 

that , "the 

whole  process  is  one 

of  'surface 

combustion1  which,  the  writer's  researches  have  shown,  is  subject 
to  special  conditions  which  do  not  apply  in  homogenous  gaseous 
combustion.  It  is  abundantly  evident  that  the  oxygen  is  first  of 
all  ’’absorbed"  by  the  coal  substance,  possibly  in  some  'activated' 
form  , then  incorporated  in  some  way  (it  may  only  be  loosely,  or, 
on  the  other  hand,  it  may  be,  as  S.W.Parr  suggested,  in  some  defi- 
nite form),  and  as  the  temperature  rises,  it  finally  is  expelled 
in  gaseous  products  (HgO  and  oxides  of  carbon).  And  between  its 
initial  absorption  and  its  final  expulsion  a whole  series  of  com- 
plex phenomena  may  be  involved,  which  have  hitherto  received  lit- 
tle attention." 

7 

Porter  and  Ralston  have  recently  done  considerable  research 
on  the  effect  of  oxygen  and  air  on  coal.  They  used  a Pittsburgh, 
a West  Virginia  and  an  Illinois  coal  and  also  a Wyoming  lignite. 
They  determined  the  total  amount  of  oxygen  absorbed  by  these  coals 
at  various  temperatures  and  pressures  and  the  amount  of  exothermic 
heat  (roughly)  from  this  absorption.  They  also  passed  air  over 
the  Illinois  and  Wyoming  coals  at  different  temperatures  and  de- 
termined the  weight  of  carbon  dioxide,  carbon  monoxide  and  water 
formed  and  the  change  in  weight  of  the  coal,  but  did  not  determine 
the  amount  of  oxygen  that  was  actually  used  during  the  tests. 


, 

- 


7. 


Porter  and  Ralstons' s conclusions  are  in  part  as  follows: 

"The  effect  of  weathering  or  of  perliminary  moderate  heating  on 
the  coking  quality  of  coal  is  explained  as  an  effect  of  oxidation 
whereby  the  fusible  organic  constituents  of  the  coal  are  decomposed 
or  altered.  The  alteration  does  not  occur  in  a nonoxidizing  at- 
mosphere. It  is  known  that  weathering  of  coal  causes  an  increase 
of  ”eombined"water ; that  is,  of  water  that  is  not  in  the  normal 
free  stat6  and  that  has  at  any  given  temperature  a vapor  pressure 
lower  than  the  normal.  This  water  remains  in  the  coal  after 
"air  drying."  Its  increase  by  weathering  is  due  to  oxidation  and 
to  the  formation  thereby  of  a complex  easily  decomposed  by  heat 
to  form  water." 

Katz®  has  shown  that  coal  will  absorb  any  gas  until  an  equil- 
ibrium with  that  gas  is  reached,  the  volume  required  depending 
upon  the  gas  used.  He  concludes  from  his  work  that,  "In  so  far  as 
investigated,  the  absorption  of  gases  by  Pittsburgh  coal  is  close- 
ly analogous  to  the  absorption  of  gases  by  charcoal." 

The  study  of  oxidation  or  weathering  of  coal  is  not  a new  to- 
pic. The  first  investigations  were  carried  on  in  an  attempt  to 
learn  something  of  deterioration  and  spontaneous  combustion  of 
coal  and  wer6  of  little  value  otherwise.  At  the  present  time  the 
same  motives  favor  investigation,  the  desired  result  being  greater 
efficiency  from  the  storage  and  use  of  coal  for  power  production. 
The  effect  of  oxygen  on  the  coking  qualities  of  coal  has  usually 
been  noted,  but  in  many  cases  given  but  slight  consideration. 

White  seems  to  have  associated  the  oxygen  content  of  coal 
with  its  coking  qualities  more  closely  than  any  one  previously, 
and  his  H:0  ratio  is  quite  applicable  as  a means  of  determining 


. 


' 


8. 


the  coking  qualities  of  most  coals. 

Bone,  and  Porter,  and  Ralston,  give  considerable  quantitative 
data  on  the  absorption  of  oxygen  oy  coal,  but  their  results  may 
be  slightly  erroneous  due  to  partial  combustion,  since  th6y  passed 
a continuous  stream  of  oxygen  over  heated  coal. 

Bone  advances  the  idea  that  the  oxygen  may  be  held  in  an  "ac- 
tivated form”  whil6  Katz  suggests  that  coal  behaves  similiarly  to 
charcoal  towards  gases.  Thus  both  hint  at  the  plausibility  of  the 
oxygen  being  held  to  the  coal  mechanically  as  a molecular  conden- 
sation or  in  an  adsorbed  condition. 

Porter  and  Ralston  explain  the  effect  of  oxidation  of  coal 
as  destroying  the  coking  constituent  by  altering  or  decomposing 

the  fusable  organic  compounds  in  the  coal. 

9 

Parr  and  Olin  sum  up  the  situation  rather  well  in  the  fol- 
lowing: "It  has  been  proved  that  oxygen  absorption  goes  on  rapid- 
ly when  fresh  coal  is  exposed  to  the  atmosphere.  It  has  been 
shown  further  that  this  absorption  weakens  or  destroys  altogether 
any  coking  properties  that  the  original  coal  may  have.  In  other 
words  a high  H:0  ratio  marks  the  absence  of  fusibility  and  cemen- 
tation. The  organic  compounds  of  the  coal  which  furnish  the  ce- 
menting material  for  the  cok6  are  apparently  attacked  by  oxygen. 
They  yield,  on  oxidation,  humic  acids  of  varying  composition  which 
decompose  into  powdery  residues.” 

Outline  of  the  Present  Investigation: 

The  initial  portion  of  the  investigation  consisted  in  a study 
of  the  effect  of  carbon  dioxide  on  the  coking  qualities  of  various 
coals.  The  coal  used  was  either  saturated  with  carbon  dioxide  and 


. 


. 


. 


9. 


carbonized,  or  it  was  carbonized  in  a current  of  carbon  dioxide. 

In  either  case  the  carbon  dioxide  used  v/as  measured  and  the  total 
gas  evolved,  also  measured  and  analyzed,  and  the  gain  or  loss  in 
carbon  dioxide  noted. 

In  studying  the  effect  of  oxygen  on  the  coking  properties, 
the  coal  v/as  in  each  case  saturated  with  the  oxygen  before  the 
carbonization  began.  This  made  it  necessary  to  determine  the  tem- 
perature best  suited  for  the  saturation,  and  the  time  necessary 

for  complete  saturation.  The  data  from  these  preliminary  oxida- 

6 

tion  tests  conforms  very  well  with  that  of  done  and  fairly  well 

7 

with  that  of  Porter  and  Ralston.  Blank  or  straight  carbonization 
tests  were  made  on  each  of  the  coals  and  the  products  determined. 
These  were  followed  by  tests  in  which  the  coal  v/as  previously  sat- 
urated v/ith  oxygen  and  again,  the  products  were  determined.  The 
resultant  gas  was  analyzed,  in  both  cases,  and  the  difference  in 
its  constituents , due  to  the  added  oxygen,  noted. 

II.  Experimental. 

Apparatus : 

The  complete  apparatus  is  shown  in  Figure  1.  For  measuring 
and  storing  the  gas  that  v/as  added  to  the  coal  two  sets  of  aspir- 
ator bottles  and  a 200  c.c.  gas  burette  v/ere  used.  These  bottles 
(A  & B)  were  of  four  and  two  liter  capacity  and  were  always  filled 
to  the  same  level  at  atmospheric  pressure.  The  burette  (G)  was 
used  to  measure  volumes  less  than  the  capacity  of  the  smaller  bot- 
tle. The  bottles  and  burette  were  connected  so  that  either  of 
the  three  could  be  filled  or  emptied  as  desired,  and  they  were  u- 
sed,  not  only  for  measuring  the  gas  passing  into  the  retort,  but 


/ 

. 


. 


10. 

also  for  that  evolved  by  the  coal.  The  wash  bottles  (D  & E)  con- 
tained sulfuric  acid  for  drying  the  used  gas  and  also  to  show  the 
rate  of  flow  of  the  gas  as  it  was  being  used.  The  gas  passed  in- 
to the  bottom  of  the  retort  (F),  under  a slight  pressure  measured 
by  the  manometer  (G). 

The  retort  used  was  made  of  pyrex  tubing  50  mm.  in  diameter 
and  45  cm.  long.  At  the  lower  end  a 10  mm.  tube  was  sealed  on  and 
a second  10  mm.  tube  or  side  arm  was  sealed  on  at  about  10  cm. 
from  the  top  of  the  retort.  The  retort  was  placed  in  the  furnace 
(T)  in  a vertical  position  with  the  upper  15  to  20  cm.  exposed. 

The  top  of  the  retort  was  closed  with  a one  hole  rubber  stopper 
carrying  a pyrex  thermocouple  tube  (P).  Heat  was  held  away  from 
the  stopper  by  two  aluminum  discs  (Q)  placed  on  the  thermocouple 
tube.  The  retort  was  in  reality  a modified  distilling  flask  with 
a side  arm  long  enough  to  act  as  a condenser.  Over  the  end  of 
the  side  arm  v/as  placed  a 50  c.  c.  distilling  flask  (H)  in  which 
the  tar  and  water  were  collected.  The  evolved  gas  passed  out 
through  the  side  arm  of  the  small  distilling  flask  into  a small 
bulb  filled  with  glass  wool,  used  to  remove  the  tar  fog.  The  man- 
ometer (G)  measured  the  pressure  of  the  evolved  gas. 

The  U tube  (K)  contained  dilute  sulfuric  acid  for  th6  removal 
of  ammonia  from  the  gas.  Hext  in  the  train  was  a CaCls  tub6  (L) 
for  removing  the  last  traces  of  water.  The  gas  next  passed  into 
a KOE  bulb  (!I)  (used  for  determining  C0o  in  organic  combustions, 
but  here  filled  with  a weakly  acid  solution  of  CdSC>4)  wbich  re- 
moved the  hydrogen  sulfide.  Prom  here  the  gas  passed  directly  in- 
to the  12  liter  aspirator  bottle  (IT)  where  it  was  stored  until 
ready  to  be  measured  in  the  previously  mentioned  bottles  (A  & B). 


. 


* 


12. 

Temperature  Control  and  Measurement: 

The  furnace  used  for  heating  the  retort  and  charge  of  coal 
was  built  in  this  laboratory.  It  consisted  of  a Chromel  heating 
element,  h6ld  on  an  Alundum  core  of  about  14  by  4 inches,  and  in- 
sulated with  Sil-O-Cel.  The  outside  container  was  an  ordinary 
can  of  approximately  16  inches  in  diameter  and  depth.  The  heat- 
ing element  was  connected  in  series  with  an  external  resistance, 
by  means  of  which  the  temperature  of  the  furnace  could  be  held  at 
any  desired  point  up  to  800  * C. , or  could  be  brought  from  room 
temperature  to  600°  C.  at  an  uniform  rate  and  in  about  two  hours 

a. 

if  desired.  In  all  of  these  tests  600  to  625°  C.  were  the  maxi- 
mum temperatures  used. 

Temperature  readings  of  the  furnace  and  of  the  center  of  the 
charge  were  taken  each  15  minutes.  Ordinary  thermometers  we re 
used  for  temperatures  up  to  250  or  300°  C.,  one  being  suspended  in 
the  furnace  between  its  wall  and  the  retort  and  the  other  being 
hung  in  the  pyrex  tube  (?)  which  passed  through  the  stopper  and 
down  to  the  center  of  the  charge  of  coal.  For  temperatures  above 
300°C.  two  Chromel -Alum© 1 thermocouples  (0),  made  of  number  16 
wire,  were  used.  These  were  connected  as  shown  in  Figure  l,.to 
a Weston  Direct  Current  Millivoltmeter  (3).  They  were  standar- 
dized against  the  freezing  points  of  Bureau  of  Standards  Aluminum 
and  Tin.  The  couples  we re  exact  duplicates  and  the  same  curve  was 
used  for  both.  The  temperatures  could  be  read  from  the  curve  to 
within  two  degrees  and  the  couples  were  accurate  to  the  same  de- 
gree. ITo  external  resistance  was  needed. 


, . 


, . 


. 

. 


. 


13. 

Operation  of  Apparatus: 

The  bottom  of  the  pyrex  retort  was  covered  with  glass  wool; 

100  grams  of  coal,  usually  ground  to  60  mesh,  wer6  poured  in  and 
the  stopper  and  thermocouple  tube  inserted.  The  retort  and  con- 
tents were  weighed  and  placed  in  the  furnace.  The  small  flask 
was  placed  over  the  side  arm  and  the  various  connections  made. 

All  pieces  of  the  train  for  collecting  the  products  were  weighed 
before  being  placed  in  position.  Thus  on  a second  weighing,  after 
the  1 6 st  was  completed,  the  weights  of  the  products  we  re  available., 

In  nearly  all  of  the  tests  using  carbon  dioxide,  the  gas  was 
passed  continuously  through  the  retort.  This  was  easily  accom- 
plished since  it  was  possible  to  fill  either  aspirator  bottle  while 
the  other  was  being  emptied.  In  all  the  tests  using  oxygen,  the 
coal  was  saturated  before  the  carbonisation  began.  The  tempera- 
ture at  which  the  coal  was  saturated  was  varied  as  desired  in  the 
different  tests.  In  some  cases,  after  the  desired  amount  of  oxy- 
gen had  been  added,  the  retort  was  swept  out  with  nitrogen  before 
the  carbonization  began,  while  in  others  this  was  thought  unneces- 
sary and  neglected. 

A number  of  tests  were  made  in  which  no  gas  was  added  to  or 
passed  through  the  coal.  These  were  termed  blank  tests  and  were 
made  in  order  that  the  effect  of  the  added  gas  could  be  more  dis- 
tinctly noted.  The  apparatus  did  not  need  to  be  altered  for  these 
tests. 

In  order  to  easily  control  the  flow  of  gas,  both  into  the  re- 
tort and  from  it,  the  auxiliary  aspirator  bottles  (A,  B & II)  were 
suspended  by  means  of  cords  and  pulleys  (not  shown  in  Figure  1.). 

In  this  manner  the  bottles  could  be  held  at  any  desired  height  and 


, 


. . 


. 


. 


14 


the  pressure  in  the  retort  easily  controled. 

The  time  of  preliminary  treatment  of  the  coal  with  oxygen 
or  carbon  dioxide  varied  and  did  not  require  close  attention.  The 
time  of  carbonization  also  varied  but  was  usually  about  three 
hours . 

Determination  of  Products  and  Analysis: 

The  most  important  products  from  the  carbonization  tests  W6re 
the  coke  residues  and  the  evolved  gases.  The  amount  of  residue, 
in  the  retort,  was  determined  by  weighing  the  coal  used  and  the 
retort  and  contents  before  and  after  the  t6st.  The  coke  was  then 
taken  from  the  retort  and  stored  in  small  glass  jars.  The  gas 
collected  in  either  or  any  of  the  bottles  A,  B,  or  K,  and  was 
measured  by  means  of  the  bottles  A and  B,  and  the  burette  G.  The 
volume  of  gas  was  in  each  case  corrected  to  60°  P.  and  30  inches 

of  mercury.  The  evolved  gas  was  analyzed  in  a Modified  Orsat  Ap- 

10 

paratus,  designed  and  built  in  this  laboratory.  The  constituents 
were  determined  as  follows:  COg  by  absorption  in  KOK,  Og  in  al- 
kaline pyrogallol,  GgHA  in  bromine  water,  and  CgHg  in  fuming 
Hp,S0^.  Hp  and  CO  were  burned  in  a copper  oxide  furnace  at  300^  G.  ; 
the  Hg  determined  by  contraction  and  the  CO  by  absorption  of  the 
resultant  CO2  in  KOH.CH4  and  CgHg  were  burned  in  oxygen  over  mer- 
cury in  a glass  bulb  and  the  two  gases  diferentiated  according  to 
Earnshaw,s'1method.  ilg  was  taken  as  the  difference  between  the 
total  of  the  above  mentioned  constituents  and  the  original  volume. 
The  original  volume  taken  was  always  100  C.C.  and  thus  the  values 
obtained  were  in  percentage  by  volume. 


■ 


15 


The  water  and  tar,  collected  in  the  flask  (H)  wer6  v/eighed 
together,  centrifuged,  and  the  volumes  determined.  Thus  the 
weights  of  each  were  obtainable . II  o attempt  was  made  to  analyze 

the  tar. 

The  apparatus  as  designed  would  also  permit  the  determination 
of  the  ammonia  and  hydrogen  sulfide  formed,  but  as  these  had  no 
direct  bearing  on  the  problem  and  since  their  determination  re- 
quired considerable  time,  none  were  made  on  the  ammonia  and  only 
a few  were  made  on  the  hydrogen  sulfide.  In  most  of  the  tests 
these  products  were  not  collected.  Probably  very  little  ammonia 
was  formed  at  the  temperatures  attained  and  the  amount  of  hydro- 
gen sulfide  depended  upon  the  coal  carbonized.  Hydrogen  sulfide 
was  observed  to  be  first  liberated  at  275  to  300°  G.  In  the  tests 
where  the  hydrogen  sulfide  was  not  removed  as  cadmium  sulfide,  it 
remained  in  the  gas  and  was  determined  as  carbon  dioxide.  Thus, 
although  the  carbon  dioxide  values  for  the  gases  analyzed  were 
high,  they  were  uniformly  so  and  the  ultimate  results  were  unef- 
fected. 

Types  of  Coal  Used: 

Two  types  of  coal  we re  used  for  these  tests,  one  was  an  Eas- 
tern Bituminous  Goal  of  the  High  Volatile  type,  from  the  Consoli- 
dated Goal  Company  of  Fairmount,  West  Virginia,  and  the  other 
type  consisted  of  several  coals  from  the  Illinois  field.  These 
were  from  Saline,  Perry,  Franklin,  and  Moultrie  Counties.  The 
Saline  and  Perry  County  coals  were  mainly  used,  the  former  being 
a good  coking  and  the  latter  a weakly  coking  coal.  The  analysis 
of  these  two  and  the  West  Virginia  coal  are  as  follows: 


. 


. 


. . 


16. 


Proximate 

Nest 

Saline 

Perry 

Virginia 

County 

County 

Moisture 

1.34 

4.27 

5.30 

Volatile  Matter 

35.76 

35.93 

35.91 

Fixed  Carbon 

56.92 

53.17 

49.85 

Ash 

5.98 

6.63 

8.96 

Ultimate 

Carbon 

78.43 

71.88 

68.00 

Hydrogen 

5.06 

4.83 

4.94 

Oxygen 

6.91 

8.32 

10.00 

Nitrogen 

1.50 

1.03 

1.66 

Sulfur 

0.78 

3.04 

1.14 

Ash 

5.98 

6.63 

8.96 

Moisture 

1.34 

4.27 

5.30 

III 

. I\6  Suit  S 

The  Effect  of  Carbon  Dioxide: 

The  results 

from  the  tests 

where  carbon 

dioxide  was  used  dur- 

ing  the  carboniz 

ation  were  all 

of  a negative 

character.  Those 

given  in  Table  1 

. show  that  carbon  dioxide  has  apparently  no  effect 

on  the  coking  constituents  of  Illinois  or  Eastern  Bituminous  coal. 

The  first  tests  with  carbon  dioxide  were 

made  on  the  West  Vir- 

ginia  coal  and  when  the  results 

were  found  to 

be  negative  it  was 

decided  that  the 

younger  coals 

of  Illinois  might  be  more  easily 

effected.  Accordingly,  tests  were  next  made 

on  a Saline  County 

coal.  Here  again  negative  results  were  obtained.  The  results  of 

these  tests  are 

shown  in  Table 

1.  as  tests  3, 

4 and  5.  In  these 

. 


' 


17 


and  other  tests  (data  not  shown)  the  conditions  were  varied  so  as 
to  attack  and  destroy  th6  coking  constituent  in  the  coal.  In  test 
number  5 the  coal  w as  held  at  its  decomposition  point  for  four 
hours  and  carbon  dioxide  passed  continuously  through  the  retort, 
but  nevertheless,  a residue  of  coke  was  obtained. 

In  test  number  6 the  residue  was  a powder.  The  coal  used  in 
this  test,  from  Franklin  County,  had  been  in  the  laboratory  for 
some  time  and  was  in  a more  or  less  weathered  condition.  A second 
test,  number  7,  was  made  on  fresh  Franklin  County  coal  and  a good 
coke  obtained.  This  proved  that  the  results  of  test  number  6 were 
due  to  the  weathered  condition  of  the  coal  and  not  to  the  carbon 
dioxide , 

In  all  these  tests  the  carbon  dioxide  was  passed  through  the 
retort  in  a continuous  stream  during  the  period  of  decomposition. 

It  was  laser  learned  that  if  the  coal,  in  a powdered  condition, 
was  heated  slightly  above  100  C.  and  evacuated  it  could  be  made  to 
"adsorb"  gases  in  a similiar  manner  as  activated  charcoal.  There- 
fore test  number  23  was  made  on  a weakly  coking  coal  from  Perry 
County,  in  which  the  coal  was  heated  to  about  180 PC.,  evacuated, 
and  carbon  dioxide  admitted.  The  coal  was  then  allowed  to  stand 
in  this  carbon  dioxide  atmosphere  for  several  hours  to  insure  com- 
plete saturation.  It  was  hoped  that  the  "adsorbed"  carbon  dioxide 
would  be  combined  sufficiently  with  the  coal  to  have  a deleterious 
effect  upon  the  coking  constituents.  However  nearly  all  of  this 
added  carbon  dioxide  was  delivered  with  the  gas  that  came  from  the 
coal  below  400  *0.  and  the  resultant  coke  was  even  better  than 
that  obtained  from  one  of  the  blank  tests  (Humber  18.)  on  this 


sam6  coal 


. , 


. 


. 


, 


- 


18 


All  of  this  data  SG6ras  to  prove,  then,  that  carbon  dioxide 
does  not  have  a deleterious  effect  upon  the  coking  coals.  And 
the  carbon  dioxide  that  is  obtained  in  the  gas  from  coking  tests 
on  non-coking  coals  must  b6  a product  of  decomposition  and  not  in 
itself  responsible  for  the  non-coking  of  the  coal.  However  this 
carbon  dioxide,  coming  as  it  does  from  the  reaction  of  oxygen  with 
carbon,  may  be  an  index  of  the  state  of  oxidation,  or  better,  the 
weathered  condition  of  the  original  coal.  And  in  this  ?/ay  the 
study  of  the  effects  of  the  two  gases  is  connected. 

The  Effect  of  Oxygen: 

The  addition  of  oxygen  continuously  during  a coking  test  is 
not  advisable  since  combustion  would  take  place  when  a temperature 
of  about  300°  C.  was  reached.  Therefore  in  the  study  of  the  ef- 
fect of  oxygen  on  the  carbonization  of  coal,  the  coal  was  satura- 
ted with  the  oxygen  before  the  carbonization  was  attempted.  In 
order  to  determine  at  which  temperature  oxygen  would  be  most  readi- 
ly adsorbed,  a series  of  tests  were  made  on  Saline  County  coal,  to 
determine  quantitatively  the  volume  taken  at  different  temperature q, 
and  the  time  of  apparent  saturation.  Temperatures  from  30  to  330*0, 
were  used  and  it  was  found  that  the  coal  took  more  oxygen  in  a 
short  time  at  a temperature  slightly  above  100 * C.  The  results  of 
these  tests  are  shown  in  Figure  II.  The  method  employed  was  to 
heat  the  coal  to  the  desired  temperature,  evacuate  as  low  as  possi- 
ble, and  admit  the  oxygen  from  a graduated  container.  The  oxygen 
did  not  pass  through  the  retort  in  which  the  coal  was  held  but 
merely  replaced  the  vacuum,  more  oxygen  being  free  to  enter  as 
needed.  As  has  been  mentioned.  Bone,  and  Porter,  and  Ralston,  have 


. 


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61 


Table  II 


. 20. 

DATA  FRO!? 

TESTS 

OK  P3REY  COUaTY  COAL. 

Tost  o*  18 

height  Coal 

100  gme 

. Carbon  Dioxide  a ide 3 

Iiono 

Residue 

67  rt 

Time 

of  addition 

— 

Tar 

10 

Carbonisation  Tenr. 

616° 

C. 

Water 

13  " 

Ti  0 

of  Carboni s 

at  ion 

3:45 

bra. 

Type  of  Re 3 i due : Poor  c o he 

f due  to  tine  of  carbonisation. 

Gas  Data: 

Fractions 

I 

II 

III 

Total 

$ 

c.o. 

c.o . 

c.c . 

% 

c.c. 

Total  Gas 

1550 

3030 

4770 

9360 

Temperature 

420* 

515  0 

615" 

616  e 

COo 

18.1 

280 

8.6  260 

C.O  286 

8.9 

826 

02 

7.3 

113 

0.9  27 

0.2  10 

1*6 

150 

c?h4 

3.2 

50 

3.5  106 

0.3  14 

1,Q 

170 

c|hS 

3.0 

46 

2.3  770 

0.2  10 

i,  ' 

126 

Hg 

2.4 

37 

14.7  445 

36.3  1730 

■ * 'Jl 

2212 

CO 

2.4 

37 

2,7  81 

10.3  492 

6.5 

610 

ch4 

16.0 

248 

44.0  1330 

42.9  2-1/45 

38.3 

3623 

c?h6 

17.0 

263 

18.0  548 

2.0  96 

9,7 

904 

■s 

30.6 

474 

5.3  160 

1*3  86 

7.7 

720 

Remarks!?  Air 

in  rot 

ort  at 

start  - 120 

c.c.  and  460 

c.c. 

»2* 

■a- 

* 

* 

* 

* » 

* # 

Test  Do#  23 

height  Coal 

100  p'i\ s.  Carbon  Di02d.de 

-4.de  d 

1630 

c « c. 

Residue 

71  " 

Tiro  of  addition 

10:00 

hr  a* 

Tar 

10  " 

Carbonisation  Temp 

61; 

0 ej 

Water 

10  " 

Tir  e of  Carboni 

sat ion  3:15 

hr  a 

Type  of  Residue:  Poor  ooke  but  slightly  better  f ■ 

.1 n in 

Test  18 

• 

Gao  Dj.it a 

Fractions 

I 

II 

111 

Total 

■ 

c.o. 

't  c.o. 

C .0  . 

€ 

c.c. 

Total  Gas 

2660 

3160 

4850 

106  7 0 

Temperature 

420" 

516* 

61;  ° 

615 

C02 

55.8 

1485 

9.0  284 

6.5  315 

19.5 

2084 

0*5 

0.3 

8 

0.3  9 

0.3  14 

0.3 

31 

c0i4 

5.2 

136 

4.5  142 

0.2  10 

2.7 

290 

c6h* 

0.4 

11 

0.8  25 

0.4  19 

0.5 

56 

si 

3.0 

80 

16.4  518 

37.1  1800 

22.4 

2398 

CO 

1.4 

37 

2.4  76 

9.7  471 

5.5 

584 

CH4 

13.1 

351 

44.4  14  2 

38.6  1872 

33.9 

3626 

CgH6 

15.3 

407 

18,2  575 

4*0  194 

11.0 

1176 

n2 

5.3 

207 

4,0  126 

3.2  166 

4.6 

488 

- Re;  arks:  Dearly  all 

of  added  COo  accounted  for  by 

analysis. 

21. 

investigated  the  absorption  of  oxygen  by  coal  to  some  extent,  but 
their  method  was  to  pass  the  oxygen  or  air  continuously  over  the 
coal  and  thus  it  would  seem  that,  at  temperatures  of  100°  C.  or 
higher,  they  were  favoring  at  least  a partial  combustion  of  the 
coal,  while  in  the  method  as  used  by  the  writer  there  seems  to  be 
no  combustion  on  the  addition  of  oxygen,  except  at  the  higher  tem- 
peratures (250  to  350°  C.). 

A second  point  of  note  is  that,  in  the  method  used,  the  com- 
plete saturation  of  the  coal  seems  to  take  place  in  a comparitive- 
ly  short  time.  In  two  different  tests  at  115  to  120°  C.  one  of 
two  and  one  half  and  the  other  of  eleven  and  one  half  hours  dura- 
tion, the  former  adsorbed  19.9  and  the  later  21.5  c.c.  of  oxygen 
per  gram  of  coal  used.  However  oxygen  would  probably  continue  to 
slowly  enter  the  coal  for  some  time.  With  the  Eastern  coal  it 
was  necessary  to  oxy  eiate  for  100  hours  before  its  coking  proper- 
ties were  destroyed  and  in  this  length  of  time  each  gram  of  coal 
adsorbed  53.9  c.c.  of  oxygen.  It  seems,  though,  that  the  Eastern 
coal  does  not  take  oxygen  as  rapidly  as  does  an  Illinois  coal. 

Having  learned  how  to  oxy 'e  iate  coal  to  the  best  advantage , 
carbonization  tests  were  made  on  the  following  coals:  A weakly 

coking  coal  from  Perry  Gounty,  and  a good  coking  coal  from  Saline 
County,  Illinois,  and,  a bituminous  coal  from  West  Virginia. 

Blank  tests  were  made  on  each  of  these  coals  to  determine  the  pro- 
ducts evolved,  two  being  made  on  the  Perry  County  coal  (tests  18 
and  19)  to  determine  the  accuracy  of  the  method.  The  results  of 
these  tests  and  of  others  to  be  discussed  are  given  in  tables  II, 
III,  IV  and  V.  The  blank  tests  were  duplicated  on  each  coal  with 
charges  that  had  been  oxidized  at  about  110*  C.  The  evolved  gas 
was  fractionally  collected  and  analyzed  in  each  test,  the  frac- 


. . 


■ 

, 

♦ • * 


22. 

tions  being  taken  each  time  at  as  near  the  same  temperatures  as 

possible . 

The  results  of  the  tests  are  shown  by  the  tables  and  graphs. 
With  both  the  Illinois  coals,  the  residue  after  treatment  with  ox- 
ygen was  a powder  with  no  indication  of  coke  structure.  In  the 
first  attempt  to  coke  the  oxiginated  West  Virginia  coal  the  resi- 
due was  partly  coked  and  partly  a powder.  In  this  test  the  coal 
had  adsorbed  about  20  c.c.  of  oxygen  per  gram.  A second  test 
was  made  in  which  the  coal  was  treated  with  oxygen  at  110°  C.  for 
100  hours  and  adsorbed  53.9  c.c.  per  gram.  The  residue  from  the 
carbonization  of  this  sample  was  similiar  to  those  from  Illinois 
coals  and  showed  no  evidence  of  softening  or  fusing. 

rr 

e) 

YJhite  classifies  coals  as  to  their  coking  qualities  by  the 
H:0  ratio.  If  the  H:0  ratios  of  the  coals  used  in  these  tests 
are  calculated  they  are  found  to  be  as  follows: 


Test  Ho.  19 

20 

21 

22 

24 

25 

26 

Coal  Perry  Perry 

Saline 

Saline 

W.Va. 

W.Va. 

W.Va 

Treatment  Blank 

Oxgd . 

Blank 

Oxgd. 

Blank 

Oxgd. 

Oxgd 

Type  Residue  Ccke 

Pw'd. 

Cole 

Pw'd. 

Coke 

Coke 

Pw'd 

H:0  Ratio  49.4 

36. 

8 58.0 

45.8 

73.2 

51.3 

33.' 

These  calculated  ratios  show  themselves  to  be  very  good  in- 
dices of  the  coking  qualities  of  the  coal  after  treatment  with 
oxygen.  The  residue  from  Test  25.  would  be  expected  to  make  a 
poor  coke  from  inspection  of  the  ratio,  51.3,  as  it  approaches 
the  lower  limit  for  coking  coals.  As  a matter  of  fact  this  resi- 
due was  not  completely  coked  and  the  portion  near  the  wall  and 
near  the  bottom  of  the  retort  was  a powder  that  had  evidently  ne- 
ver softened,  but  the  residue  in  the  center  of  th6  retort  was 


. 

• • 


. 


. 


23 


hard  dense  coke.  Evidently  the  oxygen  entering  the  coal  had  not 
diffused  thoroughly  through  it  and  the  oxygen  content  was  not  uni- 
form. Thus  the  ratio,  51.3,  would  not  hold  for  all  portions  of 
the  coal  in  the  retort. 

The  above  H:0  ratios  are  calculated  from  the  ultimate  analy- 
sis of  the  coal  on  the  air  dry  basis,  while  White  calculates  them 
on  the  dry  basis.  But  since  in  this  laboratory  it  is  customary 
to  consider  the  moisture  as  one  of  the  constituents  of  the  coal; 
it  is  reported,  along  v/ith  the  other  constituents,  in  the  ulti- 
mate analysis.  Therefore  the  H:0  ratio,  here  calculated  on  the 
air  dry  basis,  is  the  same  as  if  it  was  calculated  on  the  dry 
basis  as  proposed  by  White. 


, • . CiJ  "X 

. 


. 


, ■ 


■Tah-I^^RLX 


Teat  Ho. 


DATA 

10 


FRO’*  T30T 
THS 


on  ?srry  oo*;::;y 
MAJESTIC  HI  IFF 


COAL. PROM 


Weight  Coal  100  gme. 

Real due  68  M 

Tar  11  M 

Vator  13 


Carbon  Dioxide  added 
Tine  of  addition 
Carbonisation  Temp. 
Tine  of  Carbonisation 


24. 

None 


615  ° C. 
3:10  hr s. 


Type  of  Residue:  Coke,  fair  quality. 

Gas  Data: 

Fraoti ons 

I 

II 

III 

Total 

dl 

P 

C .0. 

% 

o . c « 

% 

C.C. 

0.0  • 

Total  Gas 

1560 

3030 

4680 

9260 

Temperature 

425° 

515  ° 

615  ° 

615  c 

COo 

16.8 

260 

7.7 

234 

4.9 

230 

7.8 

724 

02 

4.0 

74 

0.5 

15 

0.4 

19 

1.2 

108 

OgH/i 

3.2 

50 

3.9 

113 

0.5 

23 

1,3 

181 

C6H6 

3.7 

57 

2.1 

64 

0.2 

9 

1.4 

130 

Hp 

3.1 

40 

13.2 

397 

36.0 

1685 

23.0 

2130 

CO 

1.8 

28 

3.8 

.115 

8.6 

402 

5.9 

545 

OIL 

16.8 

260 

44.7 

156  i 

41.0 

1920 

38.1 

3534 

C?H6 

17.5 

271 

19.2 

682 

4 .1 

192 

11.3 

1045 

32.3 

600 

5.0 

152 

4.3 

8 06 

9.3 

050 

Remarks : Air 

in  retort  at 

start 

e Tuals 

120 

cc  Om  and  450 

oc  ng 

Tent  JSTo.  20 


height  Coal 

100  gme. 

T ot  il  Oxy  ne n ad  \ e L 

2320  c.e. 

Residue 

71  " 

Tine  of  addition 

2:00  , 

Tar 

10  ,T 

Car b on  i s a t i o n Te  nr  > . 

6600 

Tater 

12  " 

Time  o £ Garb  oni sa  1 on 

3:30 

Type  of  Residue:  PowderGd,  no  evidence 

\ of  softening 

or  cakin'- • 

Gas  Data: 

Fractions 

* ' 

I 

II 

III 

Total 

c.c. 

% 

c.c. 

% 

c #c « 

% 

c.c. 

Total  Gas 

1740 

3036 

4840 

5616 

Temperature 

426" 

* 

m>  * 

620  s 

cog 

45.2 

740 

11,3 

346 

7.1 

344 

14.8 

1430 

°2 

7.4 

129 

0.4 

12 

0.3 

15 

1.6 

156 

GgH4 

4.1 

71 

4.5 

134 

0,5 

24 

2,4. 

229 

^6% 

1.3 

23 

1.0 

30 

0.3 

15 

0.8 

68 

Hg 

2.7 

47 

13.8 

420 

33.5 

1620 

21.7 

2087 

CO 

4.1 

71 

2.2 

67 

10.4 

540 

7.4 

670 

CH4 

4.7 

82 

31.4 

952 

36.6 

1757 

28.9 

2791 

CgH6 

20,0 

384 

24*6 

746 

6.6 

319 

14.7 

1413 

ilg 

13.3 

230 

11.0 

334 

4.8 

232 

0.3 

756 

Remarks : 1666 

c.c. 

added 

Og  not 

accounted  for 

by  analysis 

= 1.96 

gable  IV 


25 


BATA  FROi*  TS  T 3 OS  3A  *11?  JUIITI 


goat  Ho.  21 
Weight  Coal 


100  gms, 


!o&‘  .1  Oxyren  /Idod 


Ilono 


Residue 

70  ” 

Time  of  addition 

mum 

Tar 

10  ” 

Carbon! sat i on  Tern. 

620'  C. 

Water 

10  " 

fine  of  Carbonization 

3: If  hr a. 

*.f  Residue: 

Coke,  hard 

and  dense. 

Gao  Data: 


Fractions 


I 

II 

III 

Total 

* 

c.c. 

% 

c.c. 

C e 0 

. ?-•  c.c. 

Total  Gas 

1550 

3024 

6,50 

10624 

Temperature 

425* 

5 0* 

620 

° 

CO* 

10.0 

244 

0.6 

262 

*• 

0 

.6  399 

8.9  955 

°2 

0.7 

11 

0.3 

9 

0 

.4  24 

0.4  44 

c2H l 

4.2 

65 

4.0 

122 

0 

.6  36 

2.1  283 

Cr,H  6 

0.4 

6 

1.0 

55 

0 

.4  24 

ir.- 

co 

CD 

e 

o 

Hg 

6*0 

93 

14.3 

436 

iW  . *'  c>8 2U 

25.8  2749 

C0„ 

1.0 

16 

0.0 

24 

3.3  199 

2.3  239 

CH4 

c»h| 

17.5 

271 

42.2 

1287 

37 

.0  2246 

35.6  3798 

21.1 

327 

21  • 3 

649 

8 

.2  496 

13.8  1472 

Hfi 

30.1 

467 

6.7 

p ; A 

6 

*8  418 

10.2  183 

Remarks : Retort  swept  with  Tip  at  start 

. Do 

iG 

in  retort 

568  c.c. 

* 

45 

m 

* 

* 

* 

Teat  Ho.  22 

Weight  Coal 

100 

* 

Total  OXw 

iron  added 

2525  c *3, 

lie  si  due 

71  " 

Time 

of  addition 

13:00  his 

Tar 

9 " 

Carbonisation  Temp 

620*  C.  ! 

Water 

10  w 

Time 

o f Garb  ni  z a tion  3 i 45  hr  a 

Type  of  Re si 

duo:  Powdered 

, no  evidence 

of  softening 

S’ 

T} 

O 

o 

& 

o 

O&s  Data: 

Fractions 

1 

II 

III 

Total 

i 

c.c. 

% 

c.c. 

% 

c.c. 

c.c. 

Total  Gas 

2150 

3100 

6160 

11420 

Temperature 

500" 

680  d 

680  " 

GOg 

37.2 

800 

10.1 

313 

8.0 

493 

14.1  1606 

°2 

11.2 

241 

0*6 

18 

0.5 

31 

2.5  290 

c.bh 

5.0 

107 

3.2 

99 

0.3 

18 

2*0  224 

g6H5 

0.4 

9 

1.9 

59 

0.5 

31 

0.9  99 

Ho 

3.4 

73 

14.5 

450 

32,2 

8830 

84.1  2753 

CO ' 

9.8 

. 10 

3.5 

108 

7.  ) 

453 

6.6  750 

C*3$ 

13.6 

294 

44.2 

1360 

36,6 

82255 

34.3  3917 

13*4 

288 

18.0 

558 

6.0 

370 

10.6  1216 

*2 

6.0 

129 

4.0 

124 

4.9 

302 

4.9  555 

Re?  arks:  1330  c.o. 

of  added  Og 

unacc 3 unted 

for  by  analysis,  * 

1.61  ;• 


table  V*. 


26, 


DATA  FROM 


TJS3T0 


05  V.T:oT  V X :l INIA  C fa  . 


Test  No.  24 


Y.7elght  Coal 

100  gms 

• Total  Oxy  ren  added 

Hone 

Residue 

76  ” 

Time  of  addition 

— 

Tar 

15  ” 

Cart)  oni  a at  ion  T 

;enp 

605  * C. 

flator 

4 " 

Tine  of  Carbon! 

b:  vt  i on 

3 

:16  hr a. 

Type  of  Residue 

: Coke,  sli  jhtly  por  us,  avide 

noe  of 

swelling* 

Oao  Data: 

Fractions 

..  I 

II  . Ill 

Total 

fo  C.C. 

% c.c . 

» < : . 

<1 

c.c. 

Total  Gas 

1606 

3820 

5600 

10605 

Temperature 

415* 

496" 

6 ° 

005° 

COp 

15.8  216 

6.1  196  *3.9 

218 

6.5 

680 

o* 

5*8  56 

025  16  1*0 

56 

1.2 

128 

%H4 

5599  99 

6,1  196  0.5 

28 

3.0 

323 

C.H. 

2.4  40 

1.6  51  0.6 

34 

1.3 

125 

*4 

4.5  76 

9.9  318  33.5 

1875 

25.6 

8269 

CO 

0.6  10 

0.0  26  3.9 

218 

2.4 

254 

oh* 

11.2  189 

44.2  1420  46.2 

2586 

40.0 

4195 

26.3  4«'k> 

21.8  ®02  6.4 

3359 

14.4 

1513 

»8 

29.5  417 

9.0  290  4.0 

224 

9.7 

1011 

Remarks : Air  in 

retort  at 

start  - 120  c.e.  0£ 

and  45C 

> c.c. 

Ho. 

* 

m * 

#e  * * 

4f  * 

\ 

Test  Ho,  26 

Weight  Coal 

100  3Q8 . 

Total  Oxygen  added 

5395  c.c. 

Residue 

72  u 

Time  of  addition 

100: 

0 hrs. 

Tar 

12  " 

Carbonisation  T 

or  ip. 

616°  C 

Water 

6 M 

Tiro  of  Carbonization 

3:6 

0 hrs. 

Type  of  Residue 

: Powdered,  no  evidence  of  softenin 

of  coking. 

Gas  Data : 

Fractions 

I 

II  III 

j* 

Tot  1 

% c.c. 

c.c  • 

c.c. 

jtv 

c.c. 

Total  (las 

1730 

3140 

6260 

11030 

Temperature 

416° 

6 >0 d 

615  * 

615° 

43.5 

2.1 

5.5 

1.3 

2.3 
14.9 
10.8 

3.? 

5.9 


4 

36 

95 

22 

40 

£58 

18? 

151 


9.4 
1.0 
6.2 

1.5 
9.1 
6.3 

45.4 

16.1 

4*0 


286 
30 
189 
46 
277 
191 
1 00 
.439 
122 


5.3 

0.3 

0.3 

0,6 

50.0 

6.0 

44.5 

6.6 

6,5 


332 

19 

19 

38 

1880 

376 

2786 

407 

407 


IS.  2 
0.8 
2.8 
1.0 
20*0 

7.5 
39.6 

9.5 
5.7 


3468 

85 

303 

106 
2197 
825 
4362 
1 47 
631 


Remarks:  1000  c.c.  added  Op  in  evolved  gas.  Undetermined  437603. 


27 


The  volumes  of  oxygen,  carbon  dioxide,  hydrogen  and  carbon 
monoxide  are  plotted  in  Figures  IV,  V and  VI  against  the  tempera- 
tures of  fractional  collection.  Each  graph  represents  the  tests 
on  one  coal.  Thus  the  differences  in  the  constituents  evolved  by 
each  coal  under  different  conditions  are  shown.  The  oxygen  added 
to  the  coal  is  shown  to  be  given  off,  in  part,  as  carbon  dioxide 
and  carbon  monoxide,  the  former  predominating  at  the  lower  temper- 
atures and  the  latter  increasing  as  the  temperature  rises.  This 
must  be  due  in  part  to  the  reduction  of  carbon  dioxide  to  the  mon- 
oxide at  high  temperatures,  by  carbon.  The  oxygen  added  does  not 
seem  to  effect  the  volume  of  hydrogen  evolved  nor  does  it  effect 
the  volume  of  oxygen,  except  in  the  first  fraction  of  gas  taken. 
However  it  is  impossible  to  account  for  all  of  the  oxygen  added 
by  an  analysis  of  th6  evolved  gas.  In  all  probability  the  oxygen 
lost  is  in  part  retained  in  the  residue,  and  would  at  higher  tem- 
peratures b6  evolved  as  carbon  monoxide,  and  is  in  part  held  in 
the  tar.  There  is  also  the  probability  that  the  water  of  decompo- 
sition, from  the  tests  in  which  oxygen  was  added,  is  in  greater 
proportion  than  in  the  blank  tests  but  it  was  impossible  to  detar  - 
mine  this  accurately  in  these  tests.  However  the  formation  of 
water  of  decomposition  should  decrease  the  volume  of  hydrogen  in 
the  gas  and  as  the  curves  do  not  show  this  to  be  true  it  would 
seem  that  the  probability,  of  a greater  amount  of  water  of  decom- 
position, is  erroneous. 

Figure  III  shows  a comparison  of  the  adsorption  of  carbon 
dioxide,  oxygen  and  nitrogen  by  Saline  County  coal  at  ordinary 
temperatures.  Time  is  the  only  variable,  since  the  pressure  and 
temperature  remained  constant  during  the  test. 


. 


, 

. 


-S--> 


. 


vu/urne  m cuo/c  Leor/merers  Volume  in  Cubic  Centimeters 


otion 


temperatures 


Centimeters 


i 


\ 


Carbpn 


Carbon 


Monoxide 


grams 


carbonization . 


W200 


2000 


<?.vo)vi\ 


gram. 


feat  con 


TS£idi 


. 


2000 


C\ioxid&, 


Carbon 


Pmm 


hydrogen, 


valued 


100  grams 


1800 


Carboniza. 


moo 


IV.  Discussion  and  Conclusions. 


52. 


Carbon  dioxid6  lias  no  effect  upon  the  coking  constituent  of 


coal.  Its  presence  in  the  gas  from  coal  is  a result  of  the  reac- 
tion of  carbon  with  the  oxygen  hold  in  the  coal.  The  gas  from 
non-coking  and  weathered  coals  contains  large  amounts  of  carbon 
dioxide,  due  to  the  high  oxygen  content  of  these  coals. 

All  coal  as  mined  contains  some  oxygen,  chemically  combined. 
The  amount  varies  with  the  different  ranks  of  coal  and  seems  to  be 
a determining  factor  which  governs  the  coking  of  the  coal.  7, 'hen 
oxygen  is  present  beyond  certain  proportions  as  compared  to  the 
hydrogen  present,  it  is  known  that  the  coking  quality  of  the  coal 
will  be  impaired.  White  has  proposed  a H:0  ratio  which  is  quite 
accurate  and  which  serves  as  an  excellent  index  for  the  coking 
qualities  of  nearly  all  coals. 

Lump  coal  will,  on  exposure  to  gases,  absorb  them  to  a cer- 
tain extent.  Finely  divided  coal  absorbs  gases  more  rapidly  but 
does  not  necessarily  have  a greater  capacity  for  them.  Coal  shows 
a marked  avidity  for  oxygen,  and  its  behavior  towards  oxygen,  and 

other  gases,  may  be  compared  similiarly  to  that  of  activated  char- 

14 

coal.  Then  the  added  oxygen  which  is  held  by  the  coal  may  be 
assumed  to  b6  in  two  forms;  first,  as  a molecular  condensation  on 
the  particles  of  coal,  considered  as  an  "adsorbed"  condition,  and 
second,  as  a carbon-oxyg6n  complex,  essentially  a stable  solid 
oxide  or  sub  oxide  of  carbon,  which  is  considered  as  "fixed  oxygen" 
The  first  from  which  is  thought  to  be  held  mechanically  should  be 
removed  by  moderate  heating  or  evacuation.  The  second  form  should 
be  removed  by  heating  to  higher  temperatures  and  should  come  off 
as  the  two  oxides  of  carbon.  This  seems  to  be  confirmed  by  exper- 
imental data  as  also  does  the  tendancy  of  the  adsorbed  oxygen  to 


33 


change  in  time  to  the  fixed  condition. 

Coal  may  be  divided  into  two  portions  by  extraction  with  or- 

1 2 

ganic  solvents,  viz  phenol  . These  portions  should  be  termed 

the  residue  and  extract.  It  is  this  residue  that  shows  the  great- 

13 

est  avidity  for  oxygen  according  to  Cherry,  and  therefore  resem- 
bles activated  charcoal  in  its  behavior,  while  the  extract  con- 
tains the  coking  constituents  of  the  coal.  The  compounds  in  the 
extract  are  not  oxidizable  at  ordinary  temperatures  but  are  con- 
sidered as  easily  oxidized,  as  they  are  h6ld  by  the  coal,  at  or 

13 

near  the  softening  or  fusion  point  of  the  coal. 

Then,  in  the  case  of  oxiginated  or  weathered  coal  the  resi- 
due may  be  assumed  to  act  as  a carrier  of  oxygen  to  the  extract 
and  liberate  its  adsorbed  oxygen,  during  the  coking  process,  at 
precisely  the  temperature  when  it  will  be  most  reactive  with  the 
extracted  portion,  thus  destroying  the  coking  properties  of  the 
coal . 

Just  how  the  oxygen  destroys  the  coking  Qualities  of  coal  is 

9 

a matter  of  speculation.  According  to  Parr  and  Olin,  the  coking 
constituent  is  an  organic  compound,  of  a complex  nature,  that  has 
a definite  melting  point  and  that  during  the  coking  process  melts 
and  flows  through  the  coal  mass  thus  binding  it  together  and  form- 
ing a coke.  It  is  more  probably  a mixture  oljbompounds , each  with 
a definite  melting  point.  If  these  compounds  are  oxidized  one 
of  two  things  probably  takes  place.  Either  the  melting  point  of 
the  compound  will  be  raised,  due  to  the  formation  of  higher  mol- 
ecular weight  compounds,  to  such  an  extent  that  it  will  be  decom- 
posed by  heat  before  its  melting  point  is  reached;  or  the  oxida- 
tion itself  will  decompose  and  break  up  the  compounds  into  other 


. 


' 


, 


34 


unstable  compounds  of  indefinite  melting  points.  In  either  case 
the  final  decomposition  would  give  large  amounts  of  carhon  diox- 
ide and  the  residue  in  the  retort  would  show  no  sighs  of  fusion 
or  softening.  In  the  event  that  the  coal  also  holds  fixed  oxygen 
an  even  greater  volume  of  carbon  dioxide  would  be  evolved. 

Then,  from  the  above  assumptions,  in  the  case  of  high  oxygen 
coals,  the  melting  point  of  the  resinic  portion,  which  is  composed 
of  high  molecular  weight  compounds,  is  so  hi^h  that  in  the  coking 
process  decomposition  takes  place  before  it  is  reached,  and  this 
accounts  for  the  large  volume  of  carbon  dioxide  given  off  up  to 
rather  high  temperatures.  This  carbon  dioxide,  then,  is  an  effect 
of  the  oxygen  in  the  coal  substance. 

While,  from  the  same  assurftions,  in  the  ease  of  low  oxygen 
coals  the  resinic  portion  is  not  easily  oxidized  at  ordinary  tem- 
peratures. But  on  oxidation  of  the  coal  the  c6llulosic  portion 
takes  up  the  oxygen  and  holds  it  until,  during  the  carbonization, 
the  temperature  is  reached  where  it  will  react  with  the  resinic 
portion.  At  this  point  then,  the  cellulosic  part  delivers  to  the 
resinic  part  sufficient  oxygen  to  cause  it  to  change  into  a high- 
er melting  compound  or  to  break  up  into  compounds  of  indefinite 
physical  properties.  And  thus  may  be  explained  the  mechanics  of 
the  effect  of  adsorbed  oxygen  on  the  coking  constituents  of  coal. 

Whether  the  coal  is  originally  high  in  oxygen  or  has  had  oxy- 
gen added  in  the  process  of  weathering  seems  to  matter  little  anl 
to  all  practical  purposes  the  effects  and  results  are  the  same. 

The  theories  just  proposed  are  tendered  as  plausible  and  pro- 
bable explanations  of  the  effect  of  oxygen  on  the  carbonization  of 
coal.  They  are  strengthened  by  the  data  obtained  during  this  in- 


. 

•-  • • >- 


* 


35. 

vestigation  and  also  from  other  sources.  It  is  not  the  intention 
of  the  writer  to  disprove  other  existing  theories  on  carbonization 
nor  to  propose  these  as  proven  facts,  but  as  theoretical  consi- 
derations worthy  of  further  study  and  investigation,  and  as  such 
it  is  hoped  that  they  will  prove  to  be  of  value. 


36  • 


V.  Summary. 

Carbon  dioxide  adsorbed  by  coal  or  passed  through  the 
retort  during  the  carboni zation  process  has  no  effect  upon 
the  coking  qualities  of  coal. 

A coking  coal  if  saturated  with  sufficient  oxygen  will 
refuse  to  coke. 

The  H:0  ration  is  an  excellent  index  of  the  coking  prop 
erties  of  a weathered  or  oxidized  coal  as  well  as  of  a fresh 
coal. 


The  oxygen  adsorbed  by  coal  is  delivered  during  the 
carbonization,  mostly  as  oxides  of  carbon.  That  portion 
unaccounted  for  must  necessarily  remain  in  the  tar  and  the 
residue . 

Finely  ground  coal  possesses  an  avidity  for  gases,  and 
especially  oxygen,  very  similiar  to  that  of  activated  char- 
coal . 


Adsorbed  oxygen  destroys  the  coking  properties  of  coal 
by  apparently  reacting  with  the  phenol  soluble  portion  during 
the  carbonization,  and  changing  it,  into  compounds  of  such 
high  melting  point  that  they  decompose  before  this  point  is 
reached,  or  into  compounds  of  indefinite  physical  properties. 

Carbon  dioxide  is  a product  of  the  decomposition  of  the 
oxiginated  phenol  extract  and  the  probable  carbon-oxygen 
complex  (sub-oxides  of  carbon  or  fixed  oxygen). 


. 1 


37 


Bibliography. 


1.  Anderson  and  Roberts,  J.  S.  C.  I.  (1898)  p 1013 
(abstracted  in  Lewes  text  (1914)  P 212) 

2.  Anderson  and  Roberts,  J.  3.  C.  I.  (1898)  p 1005 

3.  Bureau  of  Mines  Bulletin  29.  by  David  White.  (1911) 

(The  Effect  of  Oxygen  in  Goal) 

4.  Y/. A. Bone,  text,  "Goal  and  its  Scientific  Uses"  p 152 

5.  W. A. Bone,  text,  " ” " " " p 157 

6.  W. A. Bone,  text,  ” M " " ’*  p 158-62 

7.  Tech.  Paper  65.  Bur.  Min.  Porter  and  Ralston.  (1914) 

(A  Study  of  the  Oxidation  of  Goal) 

8.  Tech.  Paper  170.  Bur.  Mines,  by  S.H.Katz.  (1917) 

(The  Diffusion  of  Oxygen  Through  Stored  Goal) 

9.  U of  I Bulletin  60,  by  3. W. Parr  and  H.L.Olin.  (1912) 

(The  Coking  of  Coal  at  Low  Temperatures) 

10.  S.W.Parr,  text.  The  Chemical  Examination  of  ’Water,  Fuel, 
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11.  J.  of  the  Franklin  Inst.  154 , pp.  161-76.  (1898) 

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( Th.6  Analysis  of  Goal  with  Phenol  as  a Solvent) 

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(The  Effect  of  Oxygen  on  the  Coking  of  Coal) 

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